When I was about to move into my new house more than a year ago the first thing I ordered was the metal grills. My old time iron smith Mr. Watt Soon Yin who had been fixing the grills for my old house advised me to fix quality grills. He pointed to me the grills of my neighbour's house which he deemed was made of thin metal. Thives can easily get into the house by cutting the grills, he said. He also demonstrated to me how my aluminum framed glass sliding doors can be plied open easily.
How true my iron smith is when my neighbour's house was broken into this early morning. The thief or thieves cut the the iron around the locks thus sliding open the front grill easily. Then he/they jacked the sliding glass doors and went inside. He or they did not touch the locks.
He/they took among other things my neighbour's laptop, purse containing cash, identity and credit cards.
So for those of you thinking of fixing grills to your house don't be thrifty and regret later.